Direct-to-library methods, systems, and compositions

A method of preparing a nucleic acid library from an initial sample, comprising:

• (a) adding one or more process control molecules to the initial sample to provide a spiked initial sample, wherein the one or more process control molecules are synthetic nucleic acids;
• and
• (b) generating a nucleic acid library from the spiked initial sample, wherein generating the nucleic acid library comprises attaching one or more adapters to nucleic acids in the spiked initial sample, wherein the one or more adapters comprise an overhang region and a double-stranded region;
• wherein nucleic acids used to generate the nucleic acid library are not extracted from the initial sample nor the spiked initial sample before the attaching the one or more adapters.